JP3174271B2 - Molding composition for lamp reflector, method for producing lamp reflector using the same, and lamp reflector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding composition for a lamp reflector, particularly to a molding composition for a lamp reflector suitable for use in headlamps, fog lamps and the like mounted on automobiles, and a lamp reflector using the same. The present invention relates to a mirror manufacturing method and a lamp reflecting mirror.

[0002]

2. Description of the Related Art A lamp reflector, particularly a lamp reflector such as a headlamp or a fog lamp, uses a very high-intensity light bulb and must withstand high heat generated from a filament during use. Is formed of a thermosetting resin, and an unsaturated polyester resin molding composition has been conventionally used. For example, a thermosetting unsaturated polyester resin molding composition containing 12 to 18% by weight of glass fiber, a filler such as calcium carbonate, a fatty acid ester as a compatible internal release agent, and a curing catalyst as a curing catalyst. Reflector mirror compositions comprising an unsaturated polyester resin molding composition containing an aliphatic peroxy compound have been proposed.

[0003]

However, unsaturated polyester resins used as lamp reflectors include:
Despite the demand for heat resistance that can withstand the heat generated when the lamp is turned on (about 180 ° C.), these proposed unsaturated
When the Japanese polyester resin molding composition is used as a lamp reflector base material, thermal deformation occurs due to a rise in heat in the lamp chamber when the lamp is turned on. Further, it has been found that the base material shrinks due to the thermosetting shrinkage generated when the lamp reflector is injection-molded, and the dimensional stability and the surface smoothness are impaired. as a result,
Distortion occurs on the reflector surface, and the distortion causes the reflector surface to have an uneven surface, making it impossible to accurately control the light emitted from the light bulb. Therefore, glare may be caused to oncoming vehicles or the light distribution standard may not be satisfied. was there. In particular, since this type of high-intensity lamp reflecting mirror is required to have a highly accurate reflecting surface without optical deviation, the reflecting mirror has excellent heat resistance, dimensional stability, surface smoothness and strength. There is a need for the development of thermosetting plastic molding compounds that can provide a substrate.

[0004]

Means for Solving the Problems The present invention has been made to solve the above problems, unsaturated polyester resin, glass fiber, containing an inorganic filler and a thermoplastic resin such as unsaturated
Polyester resin molding composition (hereinafter abbreviated as molding composition)
) To form a lamp reflecting mirror. By blending a thermoplastic resin in particular according to the present invention, the thermoplastic resin expands due to heat generation at the time of thermosetting of the molding composition to compensate for the curing shrinkage of the entire system, keeping the volume of the obtained reflecting mirror constant, It is possible to form a highly accurate reflection surface without any inconsistency.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a conventionally known unsaturated polyester resin, a crosslinking agent and a catalyst can be used as a thermosetting resin substrate in a molding material for a lamp reflector. In order to withstand the high heat of 180 ° C. or higher generated from the filament, a cured product of an unsaturated polyester resin as a resin base and a crosslinking agent (hereinafter, a cured product of an unsaturated polyester resin and
It referred) a glass transition point of 0.99 ° C. or more, in particular 160 ° C.
It is preferable that it is above. When the glass transition point of the unsaturated polyester resin is 150 ° C. or higher, the elastic modulus at high temperatures can be maintained, and the reflection surface does not undulate due to thermal deformation when the lamp is turned on, and is optically favorable. The surface shape of the reflection surface can be maintained.

The unsaturated polyester resin used in the present invention is obtained by polycondensation of an unsaturated polybasic acid and, if necessary, a saturated polybasic acid and a polyhydric alcohol. As the unsaturated polybasic acid, various unsaturated polybasic acids that can be used for polycondensation can be used as appropriate, and specific examples thereof include maleic anhydride, fumaric acid, and itaconic acid, and particularly, anhydride. Maleic acid and fumaric acid are preferably used. As the optional saturated polybasic acid, various saturated polybasic acids that can be used for polycondensation can be appropriately used, and specifically, phthalic anhydride, isophthalic acid, terephthalic acid, and tetrahydrophthalic anhydride , Methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, adipic acid, sebacic acid, heptonic acid, tetrabromophthalic anhydride and the like, especially phthalic anhydride,
Isophthalic acid is preferred.

As the polyhydric alcohol, various polyhydric alcohols that can be used for polycondensation can be appropriately used. Specifically, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, , 3-butanediol, 1,4-butanediol, 1,6-hexanediol, hydrogenated bisphenol A, bisphenol A propylene oxide adduct, dibromoneopentyl glycol, pentaerythritol diallyl ether, allyl glycidyl ether, etc. Especially ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,
3-Butanediol and hydrogenated bisphenol A are preferably used.

The unsaturated polyester is preferably used in an amount of 4 to 20% by mass, more preferably 6 to 20% by mass in the molding composition of the present invention.
13 mass% is contained.

[0009] Various crosslinking agents and catalysts known in the art can be appropriately used in the molding composition of the present invention. A styrene monomer is preferably used as a crosslinking agent, and an organic peroxide such as t-butyl peroxide is preferably used as a catalyst. The crosslinking agent is preferably used in an amount of 5 to 25% by mass, more preferably 6 to 13% by mass in the present molding composition.
It can be used preferably in an amount of 0.2 to 5% by mass, more preferably 0.2 to 3% by mass in the molding composition.

As described above, in the present invention, a thermoplastic resin is added for the purpose of suppressing shrinkage during curing of the unsaturated polyester resin. Examples of the thermoplastic resin, styrene-based copolymer, polyethylene, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate or polymethyl methacrylate-based copolymer, modified ABS resin, cellulose acetate butyrate, Polycaprolactone, styrene-butadiene rubber, chloroprene rubber,
Modified polyurethane and the like can be mentioned. In particular, acrylic resins (including copolymers such as polymethyl methacrylate) (including styrene-acryl copolymers and styrene-polyester copolymers) and vinyl acetate resins (including copolymers) such as polyvinyl acetate For example, styrene-vinyl acetate copolymer) is preferable in terms of dispersibility, low shrinkage, and rigidity. The addition amount of the thermoplastic resin is preferably 2 to 12% by mass, more preferably 2.
4 to 8% by mass.

The thermoplastic resin used in the present invention has a self-heating temperature (140 to 140) at the time of curing of the unsaturated polyester resin.
180 ° C.). In order for the thermoplastic resin to fully exhibit such performance, its glass transition point must be 15 or more.
It is preferably 0 ° C. or lower, particularly preferably 120 ° C. or lower. When the glass transition point is 150 ° C. or lower, sufficient thermal expansion of the thermoplastic resin can be obtained at the time of molding, and the curing shrinkage of the unsaturated polyester can be sufficiently suppressed.

In the present invention, the dimensional stability and surface smoothness of the lamp reflector can be improved by controlling the amount of contraction of the base material and the amount of expansion of the thermoplastic resin, respectively. In particular, by setting the glass transition point of the cured unsaturated polyester resin to 150 ° C. or higher, it is possible to prevent a decrease in the elastic modulus of the reflector base when the lamp is turned on, and effectively prevent thermal deformation of the reflector base. Glass transition point 1
By mixing a thermoplastic resin having a temperature of 50 ° C. or lower, curing shrinkage of the thermosetting unsaturated polyester resin can be effectively prevented, and a highly accurate reflection surface can be formed. That is, it is possible to achieve a good balance between the contradictory performances of heat resistance and dimensional stability.

[0013] Preferred embodiments of the present invention, <br/> glass transition point 0.99 ° C. or higher of a cured product, and more preferably a 160 ° C. or more unsaturated polyester resins, a glass transition point 0.99 ° C.
Hereinafter, more preferably, an acrylic resin (including a copolymer such as styrene-acryl copolymer, styrene-polyester copolymer, etc.) such as polymethyl methacrylate at 120 ° C. to −10 ° C. or polyvinyl acetate is used. It is used in combination with a vinyl acetate resin (including a copolymer, for example, a styrene-vinyl acetate copolymer, etc.) as described above, whereby excellent dispersibility, dimensional stability, rigidity, and heat resistance are obtained. Performance can be ensured, and a good lamp reflecting mirror can be formed.

[0014] The molding composition of the present invention contains
Glass fiber is added as a reinforcing material in order to ensure strength without breakage. The addition amount of the glass fiber is preferably 5 to 30% by mass, more preferably 10 to 25% by mass in the molding composition. Within this range, sufficient impact strength can be achieved without adversely affecting the surface roughness of the molded article. The glass fiber diameter is preferably 6 to
It is 18 μm, and appropriate fluidity and strength can be ensured within this range.

The molding compositions of the present invention also contain various inorganic fillers known in the art. Examples include calcium carbonate, mica, talc, graphite, carbon black, asbestos, aluminum hydroxide and the like.
The amount of addition is not particularly limited, but is preferably about 35 to 70% by mass, more preferably about 45 to 65% by mass in the molding composition.

It is preferable to add an internal release agent to the molding composition of the present invention in order to easily remove the molded product having low shrinkage from the mold. As the internal release agent, various internal release agents known in the art can be used. For example, fatty acid metal salts such as zinc stearate, magnesium stearate, calcium stearate, and aluminum stearate are preferably used. The addition amount is preferably 0.5 to 6% by mass, more preferably 0.5 to 4% by mass. When the content is 0.5% by mass or more, the molded product can be stably removed from the mold without cracks or the like, and when the content is 6% by mass or less, the surface of the reflecting surface required as a reflecting mirror can be obtained. The treatment (primer coating) can be easily performed, and the leveling and adhesion of the coating can be sufficiently ensured.

The molding composition of the present invention may further comprise, if necessary, a pigment, a polymerization inhibitor (for example, quinones, hydroquinones, phenols, organic and inorganic copper salts, amidines, hydrazines, quaternary compounds). Contains ammonium salts, amines, nitro compounds, oximes, sulfur, polyphenols, amine hydrochlorides, etc., thickeners (eg, alkaline earth metal oxides such as magnesium oxide, calcium oxide, etc.). Can be.

FIG. 1 is a sectional view showing a typical vehicle headlamp using the molding composition of the present invention for a reflector. In FIG. 1, a vehicle headlamp 1 has a lamp chamber 6 formed by a lamp body 2 and a front lens 4 attached to a front opening of the lamp body 2. 3 and a light bulb 5 attached to the reflector. This reflector 3
Is composed of a main reflecting surface 3b composed of a radiation surface and the like and flat surfaces 3a and 3c formed vertically above and below the main reflecting surface. The surface is undercoated, and aluminum is deposited thereon to reflect the light. After the treatment, a top coat is applied.

When the light bulb 5 is turned on, the irradiation light from the filament 7 is reflected forward by the reflecting surface 3b,
Illuminate the front of the vehicle. At this time, the temperature inside the lamp chamber 6 rises due to the heat generated from the bulb 5, and particularly the surface temperature of the reflecting mirror 3 rises to about 180 ° C. Therefore, a material must be selected that allows the reflector, especially the reflector surface, to withstand these high temperatures.

The reflector 3 is formed from the unsaturated polyester molding composition according to the present invention. Unsaturated polyester 4 ~
20% by mass, 5 to 30% by mass of glass fiber, inorganic filler 3
5 to 70% by weight and 2 to 12% by weight of a thermoplastic resin, and if necessary, 5 to 25% by weight of a crosslinking agent, and 0.2 to 5% of a catalyst.
% By mass and 0.5 to 6% by mass of the internal release agent are mixed and dispersed in a mold having an appropriate shape, preferably by an injection molding method or an injection compression molding method, and then cured by heating. Thus, the reflector base 11 is obtained. Here, in order to reduce the pressure in the mold cavity before injection,
Preferably, a tank connected to a vacuum source is connected to the mold to remove air from the mold cavity before injection. When curing, the mold is preferably 130 to 200
C., more preferably 140-180.degree. The curing time can be appropriately set according to the intended thickness of the reflector base, but is preferably about 0.5 to 4 minutes. According to the present invention, almost no shrinkage of the molding composition at the time of curing was observed, and the surface condition of the reflector base removed from the mold was very good, with no distortion and high gloss.

Next, it is preferable to apply a primer as an undercoat on the surface of the reflecting mirror 3 to activate the surface. One or more lacquers may be applied on this primer coat. Next, a metal film such as aluminum is formed thereon by a vacuum evaporation method or a sputtering method to form a reflecting mirror surface. The lacquer adheres to the reflective mirror surface and the reflective aluminum film, and is preferably made of polyester, polybutadiene, epoxy, acrylic or alkyd resin. Further, a lacquer protective film may be provided on the metal film.

[0022]

【Example】

Example 1 Unsaturated polyester (polycondensate of maleic acid, orthophthalic acid, propylene glycol and neopentyl glycol; the glass transition point is as shown in Table 1) 10
Mass%, crosslinking agent (styrene monomer) 13 mass%, thermoplastic resin (vinyl acetate) 6 mass%, catalyst (t-butyl peroxybenzoate) 2 mass%, internal release agent (zinc stearate) 4 mass%, Inorganic filler (calcium carbonate)
40% by mass and glass fiber (glass fiber diameter 15 μm) 2
5% by mass was dispersed to form a molding composition. As described above, the composition was thermally cured at a temperature of 140 ° C. for 2.5 minutes by an injection molding method and removed from the mold to produce a reflector base.

A heat resistance test at 180 ° C. for 100 hours was performed on each of the obtained reflector bases, and the surface roughness (R _max ) is shown in Table 1. The surface roughness was measured according to JIS B0601 (the same applies hereinafter). FIG. 2 shows the results of a dynamic viscoelasticity test (10 Hz, 5 ° C./min heating) of each reflector base.

[0024]

[Table 1]

From the results shown in Table 1, the value of Rmax is 1.5 μm
If it is below, it can be practically used as a reflecting mirror. It can be seen that good surface smoothness can be obtained when the glass transition point of the cured unsaturated polyester resin is 150 ° C. or higher. FIG.
From the results, it can be seen that when the glass transition point of the cured unsaturated polyester resin is 150 ° C. or higher, a sufficiently good elastic modulus is maintained even at a temperature of 180 ° C. where heat resistance is actually required. In particular, when the glass transition point is 160 ° C. or more, a sufficient decrease in storage modulus is small and sufficient rigidity can be obtained.

Example 2 In Example 1, an unsaturated polyester resin having a glass transition point of 160 ° C. of the cured product was used, and the glass transition point of the thermoplastic resin was changed as shown in Table 2. A reflector substrate was manufactured in the same manner as described above. Table 2 shows the molding shrinkage, surface roughness (Rmax), sink marks on the back surface of the flange portion, and the elastic modulus of the BMC molded product of each of the obtained reflector bases.

[0027]

[Table 2]

The value of the molding shrinkage is 0.10% or less, R _max
Is 1.5 μm or less, and the sink on the back of the flange is 20 μm.
m or less, and when the elastic modulus is 10,000 MPa or more, it can be said that the reflective mirror has good performance. It can be seen that when the glass transition point of the thermoplastic resin is 150 ° C. or less, particularly 120 ° C. or less, good molding shrinkage and surface roughness can be obtained. In addition, if the glass transition point of the thermoplastic resin is 150 ° C. or less, it is practical if there is a flange portion outside the reflection effective surface. In particular, even if the reflecting surface has a flange portion, there is no sink on the reflecting surface, and the elasticity of the BMC molded product can be secured.
C-120C is good.

Example 3 In Example 1, an unsaturated polyester resin having a glass transition point of 160 ° C. of the cured product was used, and the content of the glass fiber was changed as shown in Table 3 (in the reflection mirror molding composition). (Indicated by mass% in the above), and a reflector base was manufactured in the same manner as in Example 1. The Izod impact (notched), Charpy impact and surface roughness (Rma
x) is shown in Table 3.

[0030]

[Table 3]

The value of the Izod impact (with notch) is 40
When the value of Charpy impact is 50 Ncm / cm ² or more, it can be practically used as a reflector. 5.0-3
It can be seen that within the range of 0.0% by mass, good results are obtained in both impact resistance and surface properties. In addition, when the glass fiber content is excessive, the fluidity at the time of molding is reduced and surface cracks are generated, so that the strength is reduced.

Example 4 A reflector was prepared in the same manner as in Example 1 except that unsaturated polyester having a glass transition point of 160 ° C. was used and the fiber diameter of the glass fiber was changed as shown in Table 4. A substrate was manufactured. Table 4 shows the flow viscosity, bending strength and Izod impact strength of each of the obtained reflector bases.

[0033]

[Table 4]

The value of the flow viscosity is from 80,000 to 120,0.
When the value of the bending strength is 00 MPa or more and the value of the Izod impact strength is 40 Ncm / cm or more, it can be practically used as a reflector. Glass fibers having a fiber diameter of 3 μm cause problems such as thread breakage during the production of glass fibers and increase the production cost. Further, since the surface area per unit weight of the glass fiber increases, the required fluidity during the injection molding of the reflecting mirror cannot be obtained. On the other hand, when the fiber diameter is 20 μm, the contact area between the unsaturated polyester resin and the glass fiber decreases, so that the bending strength and the impact strength decrease. It can be seen that good results are obtained when the fiber diameter of the glass fiber is in the range of 6 to 18 μm.

[0035]

According to the thermosetting plastic molding material of the present invention, a reflector base having excellent heat resistance, dimensional stability, surface smoothness and strength can be provided, and a lamp reflector having excellent performance can be manufactured. it can. Further, the glass transition point of the cured product is 1
By using an unsaturated polyester resin having a temperature of 50 ° C. or more and a thermoplastic resin having a glass transition point of 150 ° C. or less, a decrease in the elastic modulus of the reflector base when the lamp is turned on is prevented, and thermal deformation of the reflector base is effectively prevented As well as effectively prevent curing shrinkage of the thermosetting resin and form a highly accurate reflective surface,
It is possible to balance the opposing performances of heat resistance and dimensional stability in a well-balanced manner.

Particularly, an unsaturated polyester resin having a glass transition point of 160 ° C. or higher of the cured product, and a glass transition point of 120 ° C. or higher.
By using in combination with acrylic resin (including copolymer) or vinyl acetate resin (including copolymer) at -10 ° C, excellent performance is obtained in all of dispersibility, dimensional stability, rigidity and heat resistance. The lamp reflector base can be molded. Furthermore, by using glass fibers having a diameter of 6 to 18 μm, appropriate fluidity and strength can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a vehicle headlamp using a molding composition of the present invention for a reflector base.

FIG. 2 is a graph showing the temperature dependence of the elastic modulus with respect to Tg of a cured unsaturated polyester resin .

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI G02B 5/08 G02B 5/08 A (56) References JP-A-5-242701 (JP, A) JP-A-5-128904 ( JP, A) JP-A-3-208201 (JP, A) JP-A-4-506682 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F21V 7/22 G02B 5/08 C08K 3/00 C08L 1/00

Claims (5)

(57) [Claims] 1. An unsaturated polyester resin, glass fiber,
Unsaturated polyester containing inorganic filler and thermoplastic resin
Glass transition point of the thermoset resin is 150 ° C or higher, thermoplastic
A molding composition for a lamp reflector , wherein the glass transition point of the reactive resin is 150 ° C. or lower . 2. The unsaturated polyester resin cured product has a glass transition point of 160 ° C. or higher, and the thermoplastic resin is at least one selected from an acrylic resin (including a copolymer) and a vinyl acetate resin (including a copolymer). It contains one resin and has a glass transition point of from 120 ° C to -10
A ° C., claim 1 lamp reflector molding composition. 3. The molding composition for a lamp reflector according to claim 1, wherein the fiber diameter of the glass fiber is 6 to 18 μm. 4. The method of claim 1 by molding curing the composition according to any of 3 to give the reflector substrate, the manufacturing method of the lamp reflector to form a metallic reflective coating on the interior surface of the substrate. 5. A reflector base obtained by molding curing the composition according to any one of claims 1 to 3 lamp reflector and having a metallic reflective coating on its inner surface.